As its 50th anniversary nears, Universal Studios Hollywood is undergoing a level of construction unlike anything the movie theme park has seen in the last half-century.

Virtually every corner of Universal -- the parking structures, the main entrance, the theme park, the studio backlot -- is under construction, all in anticipation of a certain boy wizard.

“There's more construction going on now than ever before, probably in the history of the park,” said Jon Primrose, editor of the Studio Tour, a Universal Studios fan site. “But how will the park cope when the Wizarding World of Harry Potter opens its gates? It's already full of people.”

The nearly constant dust and din of the massive expansion marks quite a turnaround for a park that was down on its heels at the beginning of this decade. If the last five years or so have proved immensely successful for Universal, the five years before that were a total disaster -- both figuratively and literally.

After the twin successes of the Shrek 4-D film in 2003 and the Revenge of the Mummy indoor roller coaster in 2004, Universal Studios Hollywood entered a low period creatively that stretched through the end of the decade. In retrospect, much of the blame can be pinned on the merger of NBC with Vivendi Universal Entertainment in 2004.

“Between 2003 and 2010, there were some very strange decisions made as Universal Studios Hollywood seemed to be struggling with its identity,” said Primrose. “Too many of the new attractions had no story, no heart, no emotion.”

The bad streak included one horrible new attraction after another: "Fear Factor Live" stage show (2005), Fast & Furious: Extreme Close-Up dancing stunt cars (2006), House of Horrors walk-through maze (2007), Curious George water play area (2008) and the "Creature from the Black Lagoon" stage musical (2009).

Many of the woeful new additions replaced attractions that were as bad or worse than their successors. Anyone remember the "Spider-Man Rocks" stage show or the Chicken Run walk-through maze? It’s not surprising since neither of these attractions remains.

“Much of the period could be characterized by a combination of corporate ambivalence, aimlessness and general stagnation -- all in an effort to streamline costs,” said Jonathan Fu, editor in chief of the Inside Universal fan site. “When Universal did choose to invest, attractions were often met with a lukewarm response, attributed mostly to poor execution or limitations stemming from low budgets.”

The fallow period produced only two unqualified successes: the triumphant return of Halloween Horror Nights and the new Simpsons ride (unless you were a fan of the old Back to the Future ride).

By far the lowest of the lowlights during that forgettable era was the 2008 studio backlot fire that destroyed the New York City streets and the King Kong attraction.

“A big symbolic change was the huge and devastating fire in 2008,” said the Studio Tour’s Primrose. “King Kong had been the centerpiece of the studio tour since 1986. It was one of the symbolic and tone-setting attractions in the park. Totally story-led, very immersive, very successful.”

In retrospect, the devastating fire proved a blessing in disguise, allowing the theme park to rise from the ashes like a phoenix. The Kong attraction’s smoldering remains were replaced in 2010 with the spectacular King Kong 360 3-D drive-through movie experience that immediately became a highlight of the studio tram tour.

“Much in the same vein of Universal’s now-classic attractions of the '90s, King Kong was the embodiment of Universal’s best creative traits,” said Inside Universal’s Fu. “Not only was the attraction unapologetically boisterous, groundbreaking and loud, it also resonated deeply with the public -- allowing guests to interact with their favorite characters in a new, innovative way.”

The new Kong attraction set a high bar for attraction quality and excitement at Universal and heralded a sustained run of well-received rides and themed lands.

Since then, Universal has embarked on a five-year plan that has seen the introduction of the Transformers 3-D dark ride (2012), Despicable Me: Minion Mayhem motion simulator (2014) and the Simpsons-themed land of Springfield (April 2015) with the Fast & Furious: Supercharged drive-through movie (June 25) and the Wizarding World of Harry Potter themed land (Spring 2016) still on the way.

So what changed?

First, Universal found the key to Gringotts Bank in 2010 when the wildly successful Wizarding World of Harry Potter opened in Florida. Annual attendance in Orlando rose 20%, revenue soared by more than 40% and operating profit nearly quadrupled as fans scooped up magic wands and downed millions of butterbeers, according to the Orlando Sentinel. The Potter bounty was poured back into Universal parks worldwide, including California.

Second, Comcast took controlling interest of NBCUniversal and increased theme park revenue from $400 million in 2011 to an expected $1.3 billion in 2015 at the Florida and California locations.

The changes have had an immediate and striking effect on Universal Studios Hollywood. Annual attendance has risen from 4.3 million visitors in 2009 to 6.1 million in 2013, according to the Themed Entertainment Assn. And that number is expected to skyrocket when Potter finally opens.

So what’s next? Universal officials aren’t commenting, but a multi-decade evolution plan for the park unveiled in 2006 offers some clues.

The $7-billion evolution plan calls for seven new theme park attractions and the removal or relocation of several studio backlot tour favorites, including the "Jaws" lake, the "War of the Worlds" disaster scene and the famed "Psycho" house and Bates Motel.

A pair of aging theaters located side by side on the Upper Lot would seem like a perfect spot for a new attraction. The Animal Actors stage that opened in 1970 feels quaintly archaic alongside the park’s newer high-adrenaline attractions while the nearby 1979 Castle Theater is currently home to the equally out-dated Special Effects Stage.

Universal recently announced a partnership with Nintendo to introduce interactive theme park rides based on video games such as Super Mario Bros., Donkey Kong and Legend of Zelda. The hope is to draw gamers to the parks who have played some of the 4.3 billion Nintendo video games sold since 1983.

And how about this as a suitable finale for Universal’s five-year plan: A Diagon Alley expansion of Wizarding World is reportedly envisioned for the Waterworld stunt show arena location, according to a source who has seen the blueprints.

“The concept of Diagon Alley coming to Hollywood seems to get tossed around a lot within the theme park community,” said Inside Universal’s Fu. “While I’m a bit bearish on the idea itself, given the park’s current layout and space predicament, I think it’s also important to note Universal’s penchant for defying the status quo in terms of what can and cannot be done on its Hollywood property.”